Thermostat.



E. P. ALEXANDER.

THERMOSTAT.

APPLICATION nuzu MAR. 20, 1915.

1,199,225.- PatentedSept. 26,1916.

1 .by I,

Attorneys,

UNITED STATES PATENT OFFICE.

. EL'MER P. ALEXANDER, F YEAGERTOWN, PELTNSYLVANIA.

THERMOSTAT.

Specification of Letters Patent.

Patented Sept. 26, 1916.

Application filed March 20, 1915. Serial No. 15,890..

To'all whom it may concern:

Be it known that I, ELMER P. ALEXANDER,

a'citizen of the United States, residing at Yeagertown, in. the county of Mifliin and State of Pennsylvania, have invented a new and useful Thermostat, of which the following is a specification.

This invention relates to thermostats utilizing metals having different coefficients of expansion, one of the objects of the invention being to provide a simple and compact thermostat which is extremely sensitive in operation and the members of which are so assembled as to be capable of producing an extensive movement of the parts controlled by the thermostat without complicating the structure of the thermostat or necessitating the 'use'of a thermostat which is undesirably large.

. It is necessary under some conditions to, utilize a thermostat which will respond to the slightest variation in temperature and it v is an object of the present invention topro- 'vide expansible members soarranged relative to each other that the slightest variation in temperature will result in an immediate that changes in the precise embodiment of the invention herein disclosed, can be made within the scope of what is claimed, without departing from the spirt of the invention.

In the accompanying drawings the preferred form of the invention has been shown.

In said drawings Figure 1 is a view partly in'elevation and partly in section of a thermostat embodying the present improvements. Fig. 2 is an end elevation of the thermostat, the same being shown connected to the damper lever of a heater such as used for example in connection with incubators. Fig. 3 is a plan view of the Fig. 4c is an enlarged section on line AB Fig. 1. Fig. 5 is a perspective view of a portion of the thermostat.

Referring to the figures by characters of reference 1 designates a channeled bar fixedly connected at one end to a hanger 2 which can be in the form of a tube as shown ers.

. and, at its other end, to a bracket 3 which can be mounted upon a suitable supporting structure such as a wall of an incubator casing, a portion of which structure has been shown at 4:. A hinge member 5 is connected to or'formed with that end of the bar 1 remote from the hanger 2 and is connected to another hinge member 6 at one end of a channeled bar 7, the other end of the bar 7 having its side flanges cutaway, as shown particularly in Fig. 5, thus to provide a fiat ear or extension 8 for engagement by a rod 9 or the like to be actuated by the thermostat. Y

Formed within each of the bars 1 and 7 at those ends thereof remote from the hinge members 5 and 6 are longitudinal slots 10.

Interposedbetween the bars 1 and 7 are metal angle strips having a high coefficient of expansion and which are hereinafter deslgnated as expanders, these strips being indicated at 11 and 12 respectively. The two expanders are oppositely disposed, the

flange of one of the expanders being extended upwardlyat one end into the slot 10 in bar 1, while the flange of the other expander is extended downwardly at one end into the slot 10 in the bar 7. The two bars are offset relative to each other .and cross between their ends, expander 11 being secured at one end to that end of bar 1 nearest hanger 2 and at its other end to that end of bar 7 nearest the hinge member 6. Ex-

pander 12 is secured at one end to the bar 1 close to the-hinge member 5, and at its other end to bar 7 close to the ear 8. It will be noted, particularly by referring to Fig. 5, that the flanges of the expanders do not extend up to the ends of said expanders but terminateat the inner edges of laterally extending cars 13 riveted or otherwise secured to the bars. Thus the flanges of the expanders do not prevent said expanders from bending at the cars 13 along lines extending transversely of the expand- By mounting the bars'l and 7 and the expanders 11 and 12 in the manner described it will be apparent that when the thermostat is subjected to the action of increased heat, the expander 11, as it elongates, will thrust longitudinally against the bar 7 at its point of connection therewith, thus swinging said bar 7 downwardly around its hinge connection with expander 11 and likewise causing the expander 12 to swing downwardly with the bar 7, said expander 12 bending close to its point of connection with the bar tion 9 a distance suitable for all practical purposes.

Importance is attached to the fact that m order to multiply the movement of the expanders, it is not necessary to provide a bulky structure made up of a number 'of parts and, consequently, the thermostat herein described will be found especially useful in small structures, such as menbators and the like.

Where the thermostat is used for operating a damper, thereby to control a heater, it is preferred to use mechanism such as has been shown in detail in Fig. 2. This mechanism includes a damper lever 14 having knife edges 15 supported by bearings 16, said damper lever being provided with the usual counterbalancing weight 17 and. being connected, at one end, to a damper 18. Instead of connecting the rod 9 directly to one arm of the lever 14, it is attached to a bowed spring 19 secured at one end upon the lever, as at 20, the other end of the bowed sprlng being extended through or past the lever and engaging the rod 9. Thus when the rod is pulled downwardly by the thermostat,

motion is transmitted therefrom to the damper lever through the spring 19 which operates as a cushioning means, thus preventing the knife edges from binding too tightly on their supports or bearings 16.

' The tension of the spring 19 can be controlled by a nut 21 bearing downwardly on the spring and adjustably engaging a screw 22 which projects upwardly from the le ver 14,

What is claimed is 1. A thermostat having crossed expanders each anchored at one end, and a movable member secured to the movable ends of the expanders, each expander being bendable solely at its ends.

2. A thermostat having crossed expanders each anchored at one end, and a pivoted member secured to the movable ends of the expanders, each expander having bendable end portions and being rigid between said end portions.

3. A thermostat having crossed expanders each anchored at one end, and a movable member pivotally mounted at one end and secured to the movable ends of the expanders, each expander having bendable end portions and being rigid between sald end portions.

4-. A thermostat having crossed longitudinally stiffened expanders bendable only at their ends and each anchored at one end, and a movable member secured to the movable bendable ends of the expanders.

5. A thermostat having crossed longitudinally stifi'ened expanders bendable only at their ends and each anchored at one end, and a pivoted member secured to the movable bendable ends of the expanders.

6. A thermostat having crossed longitudinally stiffened expanders bendable only at their ends and each anchored at one end, and a rigid member fulcrumed at one end and secured adjacent its ends to the movable bendable ends of the expanders.

7. A thermostat including a fixed bar, a movable bar hingedly connected at one end thereto, and crossed expanders anchored at 8. A thermostat including a fixed bar, a

movable bar hingedly connected at one end to the fixed bar, expanders having bendable end portions and rigid between said end portions, said expanders being secured to the respective ends of the fixed bar, said expanders being crossed and being secured to the respective ends of the movable bar.

9. A thermostat including a fixed bar, a movable bar hingedly connected at one end thereto, longitudinally stiffened expanders secured at one end to the end portions of the fixed bar, said expanders being crossed and being bendable adjacent their ends, the other ends of the expanders being secured to the respective ends of the movable bar.

' 10. A thermostat including a fixed bar, a movable bar hingedly connected thereto, said bars having longitudinal slots, expanders secured at one end to the respective ends of the fixed bar, said expanders being crossed and secured at their other ends of the respective 7 ends of the movable bar, there being longitudinally'extending stiffening flanges upon the expanders and projecting into the slots.

11. The combination with a damper lever and a spring connected thereto, of a thermostat including a hinged bar, an expander anchored at one end and secured at its other ver, thermostatically controlled means enover the fulcrum of the legaging the free end of the spring for actuating the lever,-and means upon the lever for varying the tension of the spring.

In testimony that I claim the foregoing as 15 my own, I have hereto aifixed my signature in the presence of two Witnesses.

ELMER P. ALEXANDER.

Witnesses:

WM. H. WHEN, L. V. ALEXANDER. 

